1. Field of the Invention
The present invention relates to fuel transfer from a fuel tank to an engine and, more particularly, to a method and apparatus for allowing an optimum amount of water to be transferred with fuel to the engine, wherein the optimum amount of water is an amount of water which will permit the engine to operate substantially normally while disposing of water in the fuel tank.
2. Description of the Related Art
Hydrocarbon fuels are typically utilized in, for example, automobiles, trucks, boats, and other water craft. Hydrocarbon fuels are generally transported to a typical fueling station utilizing transport trucks which carry the fuel from a refinery or storage facility to the fueling station. Fueling trucks are typically compartmentalized so that different grades of fuel may be simultaneously transported to a fuel filling station. The fuel filling station measures the amounts of particular fuel grades needed to bring its storage tanks to full and communicates this information to, for example, the fuel storage facility. Transport trucks are filled and dispatched accordingly.
Typically, many of the individual compartments of the fuel transfer truck will not be filled to capacity and will therefore contain air-filled space. As the air in the transport truck compartments cools, condensation is formed. Moisture accumulates and mixes with the fuel contained within the compartments. The thusly diluted and contaminated fuel is then deposited at a fueling station and subsequently pumped directly into a vehicle, or pumped into a transport container for later transfer into a remotely located vehicle or water craft.
Vehicle and water craft fuel tanks are, of course, not always filled to capacity. As in transport trucks, condensation forms in partially filled fuel tanks and further contaminates the fuel contained therein. Water condensation and subsequent contamination of fuel has been described with respect to fuel transport trucks and individual fuel tanks by way of example. Condensation and subsequent contamination can occur in any partially empty reservoir and is particularly problematic in large reservoirs with large amounts of air-filled space.
In addition to water contamination caused by condensation, water craft are susceptible to additional fuel contamination due to the operational environment of such craft. Water craft are typically fueled while in the water and, therefore, water may be splashed into or otherwise inadvertently introduced into the fuel tank while fueling. Additionally, water craft typically occupy areas of high humidity, which exacerbates the problem of water contamination due to condensation forming in the tanks.
Additional problems of fuel contamination are associated with small jet powered water craft or xe2x80x9cpersonal water craftxe2x80x9d. Personal water craft (PWC) are often used by individuals to execute sharp turns at high speeds as well as other maneuvers which may lead to increased occurrences of the PWC being capsized. When capsized, fuel storage and distribution parts of a water craft can be more susceptible to infiltration by water.
Water contaminated fuel can be the cause of many engine problems. Water contaminated fuel can cause rough engine operation, and loss of engine power. Problem frequency and severity increases as the water/fuel ratio increases. A high water/fuel ratio is particularly problematic at engine start. Water settles to the bottom of the fuel tank when the vehicle is at rest and therefore the xe2x80x9cfuelxe2x80x9d drawn into the engine has a very high water content. While water contaminated fuel may cause the above-mentioned problems, a certain amount of water can be run through an internal combustion engine without experiencing these problems, particularly at high engine speeds.
Generally, fuel pumps utilized in land vehicles and water craft either pump the entire water content of the fuel tank to the engine or filter substantially all the water from the fuel tank. Significant amounts of water accumulate when utilizing a system allowing substantially no water to reach the engine of a land vehicle or water craft. This accumulated water must be stored for later removal from the vehicle.
In view of the above-identified problems, systems which seek to allow a measured portion of water to reach the engine have been developed. One such system utilizes a fuel supply tank having a pair of outlets which combine at a single fluid conduit which is in direct fluid communication with a fuel pump. One of the supply tank outlets is situated at the lowermost region of the supply tank, such that water accumulating therein is continuously delivered to the fuel pump. The outlet connected to the lowermost region of the supply tank includes a flow restriction device to attempt to limit the quantity of water supplied to the fuel pump. The other of the supply tank outlets is positioned above the lowermost region of the supply tank in an effort to prevent water accumulated in the supply tank from being conducted by this outlet to the fuel pump. This system does not utilize a hydrophobic filter, and, therefore, hydrocarbon product containing a water component may be transferred via either fluid conduit exiting the fuel tank. With this in mind, this prior art fuel supply system will supply product to the fuel pump having an imprecise water/fuel ratio, which may be greater than the optimum water/fuel ratio.
The water/fuel ratio of the product provided by the system described immediately supra is susceptible to increase due to fuel sloshing. Since the amount of water delivered to the fuel pump is dependent solely on the location of the fluid conduits, if the contents of the fuel supply tank are sloshed and jostled, all of the water in the supply tank will not be contained in the lowermost region of the tank. Therefore, the conduit connected above the lowermost region of the fuel tank will many times deliver water-contaminated fuel to the fuel pump in addition to the water conveyed by the conduit connected to the lowermost region of the tank. Since this system does not utilize a hydrophobic filter to prevent water from being conducted by one of the fluid conduits exiting the fuel tank, a large amount of water could make its way to the engine. Therefore, this fuel supply system cannot consistently deliver the optimum amount of water to the engine, and thus any engine to which it is connected would be susceptible to the problems associated with water contaminated fuel.
Other systems which seek to allow a measured portion of water to reach an engine utilize complex devices. Such devices, for example, utilize dual fuel pumps and separation membranes. Other known devices utilize a venturi tube including a plurality of ports through which water may pass to introduce a measured amount of water to the fuel feed system. The water/fuel ratio provided by a delivery system utilizing a ported venturi tube is dependent solely upon the rate of fluid transfer. These systems will transfer water to an engine only at relatively high rates of fluid flow. Since systems utilizing ported venturi tubes will not transfer water to the engine at relatively slow operating speeds, these systems may experience water accumulation.
What is needed in the art is a method and apparatus for eliminating engine problems associated with water contaminated fuel while allowing an optimum amount of water to be run through the engine and avoiding water accumulation in the fuel tank.
The present invention is directed to improve upon existing methods and apparatus for transferring fuel from a fuel tank to an internal combustion engine, wherein it is desired to achieve an optimum water/fuel ratio to be run through the engine, and wherein the optimum water/fuel ratio corresponds to a water/fuel ratio which will permit the engine to operate substantially normally while disposing of water in the fuel tank. The optimum water/fuel ratio can be empirically determined for specific applications and will vary depending upon the operational condition of the engine.
The invention, in one form thereof, comprises a fuel transfer apparatus for conveying fuel from a fuel tank to an engine. In this form of the current invention a fuel pump having a pair of inlets is placed in fluid communication with both the fuel tank and the engine. A filter operable to prevent water from flowing therethrough is positioned upstream from one of the pair of fuel pump inlets. The pair of fuel pump inlets are relatively sized to achieve a water/fuel ratio which allows an amount of water to reach the engine, whereby the water reaching the engine has substantially no adverse effect on the operation of the engine.
The invention, in another form thereof, comprises a fuel transfer apparatus for conveying fuel from a fuel tank to an engine. The fuel transfer apparatus of this form of the current invention includes a fuel pump having inlet means placed in fluid communication with both the fuel tank and the engine. The apparatus of this form of the current invention utilizes filter means for preventing water from flowing through a first portion of the inlets means to achieve a water/fuel ratio allowing an amount of water to reach the engine. The amount of water reaching the engine has substantially no adverse effect on engine performance.
The invention, in another form thereof, comprises a method of conveying fuel from a fuel tank to an engine. The method of this form of the current invention includes the steps of: providing a fuel conveying device having a first inlet operable to prevent water from entering the fuel conveying device and a second inlet which allows water to enter the fuel conveying device; sizing the first inlet and the second inlet to achieve a water/fuel ratio, whereby said water/fuel ratio allows an amount of water to reach the engine, which amount of water has substantially no adverse effect on engine performance; placing the first and the second inlets in fluid communication with the fuel tank; and placing the outlet of the fuel conveying device in fluid communication with the engine.
Additional forms of the current invention include a controllably sized orifice associated with one or both of the fuel pump inlets so that the water/fuel ratio can be readily adjusted. For example, a controllably sized orifice may be operatively connected to the fuel pump inlet allowing water contaminated fuel to pass therethrough. In these embodiments, the size of this orifice can advantageously be changed depending upon, e.g., the operational state of the engine or the water content of the fuel tank. For example, the orifice size could be significantly reduced at engine start-up and enlarged as the engine achieves relatively high running speeds. In one exemplary embodiment, the controllably sized orifice is connected to and controlled by a computational/control device, e.g., a programmable logic controller or a microprocessor.
In one form of the current invention, the fuel pump inlet downstream from the hydrophobic filter is configured to access fuel maintaining a higher position in the fuel tank relative to the fuel which is accessible to the fuel pump inlet allowing water to pass to the engine. Since water settles to the bottom of a fuel tank, this configuration allows the water content of the fuel tank easier access to the non-water filtered fuel pump inlet.
An advantage of the present invention is the ability to eliminate problems associated with fuel having a high water/fuel ratio running through an internal combustion engine.
Another advantage of the present invention is the ability to eliminate problems associated with water contaminated fuel without requiring provision of a water storage facility and the periodic emptying thereof.
A further advantage of the present invention is the ability to allow water to be run through an internal combustion engine during all operational states of the engine, while eliminating the problems associated with running water contaminated fuel through an internal combustion engine.
Yet another advantage of the present invention is the ability to prevent product having an overly high water/fuel ratio from being introduced into an internal combustion engine.